Displacement measurement method based on laser self-mixing interference in the presence of speckle  

作　　者：Yan Zhao Haiwei Zhang 赵岩;张海伟(School of Electrical and Electronic Engineering,Tianjin University of Technology,Tianjin 300384,China;Tianjin Key Laboratory for Control Theory and Applications in Complicated Systems,Tianjin 300384,China;Tianjin Key Laboratory of Film Electronic and Comm unication Device,Tianjin 300384,China)

机构地区：[1]School of Electrical and Electronic Engineering,Tianjin University of Technology,Tianjin 300384,China [2]Tianjin Key Laboratory for Control Theory and Applications in Complicated Systems,Tianjin 300384,China [3]Tianjin Key Laboratory of Film Electronic and Comm unication Device,Tianjin 300384,China

出　　处：《Chinese Optics Letters》2020年第5期11-15,共5页中国光学快报（英文版）

基　　金：the National Natural Science Foundation of China(No.61803281);the Natural Science Foundation of Tianjin(Nos.18JCQNJC75500 and 18JCQNJC71200);the Scientific Research Project of Tianjin Education Commission(Nos.2017KJ253 and 2018KJ136).

摘　　要：In order to achieve the accurate measurement of displacement, this Letter presents a self-mixing interference displacement measurement method suitable for the speckle effect. Because of the speckle effect, the amplitude of the self-mixing interference signal fluctuates greatly, which will affect the measurement accuracy of displacement. The ensemble empirical mode decomposition is used to process the interference signal, which can filter out high-frequency noise and low-frequency noise at the same time. The envelope of the self-mixing interference signal is extracted by Hilbert transform, and it is used to realize the normalization of the signal. Through a series of signal processing, the influence of speckle can be effectively reduced, and the self-mixing interference signal can be transformed into standard form. The displacement can be reconstructed by fringe counting and the interpolation method. The experimental results show that the method is successfully applied to the displacement measurement in the presence of speckle, which verifies the effectiveness and feasibility of the method.

关 键 词：MEASUREMENT DISPLACEMENT LASER SELF-MIXING INTERFERENCE 

分 类 号：TN24[电子电信—物理电子学] O436.1[机械工程—光学工程]